External voltage regulators are used to provide an external voltage to operate semiconductor devices. Different portions of semiconductor devices may require different voltages. For example, the I/O portion of a chip may require a different voltage than the voltage necessary to run core logic of the chip. In addition, the voltage level that is applied to the core logic of a chip may vary between chips, depending upon process variations during manufacture of the chip. The process of adaptive voltage scaling and optimization can be used to optimize operational speeds of the core of the chip, while minimizing power consumption by adjusting the voltage level being applied to the core logic. In that regard, it is advantageous to be able to accurately control the output voltage of a voltage regulator with a high degree of precision.